20017872 has 90 divisors (see below), whose sum is σ = 65191698. Its totient is φ = 5717376.

The previous prime is 20017871. The next prime is 20017903. The reversal of 20017872 is 27871002.

It can be written as a sum of positive squares in only one way, i.e., 11861136 + 8156736 = 3444^2 + 2856^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20017871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 5638 + ... + 8474.

Almost surely, 2^20017872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20017872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32595849).

20017872 is an abundant number, since it is smaller than the sum of its proper divisors (45173826).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20017872 is a wasteful number, since it uses less digits than its factorization.

20017872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2865 (or 2849 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 20017872 is about 4474.1336591568. The cubic root of 20017872 is about 271.5225910406.

Adding to 20017872 its reverse (27871002), we get a palindrome (47888874).

The spelling of 20017872 in words is "twenty million, seventeen thousand, eight hundred seventy-two".